1. Field of the Invention
The present invention relates to a chain and a manufacturing method of a sliding member of the chain.
2. Description of the Related Art
Among various kinds of chains to be used for transmission of mechanical power such as roller chains, stainless steel chains have been widely used that are made of stainless steel whose corrosion resistance property is more excellent than that of steel. As a stainless steel used to make the stainless steel chain of this type, austenitic stainless steel, precipitation-hardened stainless steel, and the like have been know. Generally, the austenitic stainless steel is used very often, because the austenitic stainless steel is excellent in its corrosion resistance property, heat-treated in a simple manner, and relatively less expensive, as disclosed in JP-A-2003-322222.
However, the stainless steel chain made of the austenitic stainless steel, disclosed in JP-A-2003-322222, is somewhat disadvantageous in terms of hardness (strength), compared to a chain made of usual steel,.
In order to eliminate such a disadvantage, the sliding members should be made of the precipitation-hardened stainless steel, rather than the austenitic stainless steel, because the former can provide more excellent hardness. However, use of the precipitation-hardened stainless steel to produce the stainless steel chain causes other disadvantages in that complex heat treatment processes are required, and raw materials are relatively expensive, compared to the stainless steel chain made of the austenitic stainless steel.